The invention resides in the field of mechanics and precision mechanics and relates to rotors for fluid pumps.
Such pumps can be used in various ways in different spheres. In particular for use in surroundings which are difficult to access, it can be sensible to use compressible and expandable rotors in order to bring these in the compressed state to a place of use and to expand there in order to put be put into operation. Special applications are for example with pumps for circuitous pipe systems.
A further special application of such pumps takes place in the medical sphere. Pumps are used there in particular in the invasive field, i.e. introduced into the body of a patient. It is known to convey pumps in different forms, for example as catheter pumps, through natural body vessels, for example blood vessels, and to operate them there or for example also in a ventricle. For such special applications, a corresponding pump must have a particularly small construction, which concerns the radial diameter.
In order to design such pumps to be easily compressible and expandable, various measures are possible. Thus for example mechanisms have become known in order to design blades on corresponding pump rotors to be articulated and unfoldable and foldable radially. Rotors consisting also at least partially of so-called memory materials have become known, which change their shape as a function of the ambient temperature and are expandable or compressible in this way.
For example a compressible and expandable rotor (impeller) with a hub which carries various blades is known from US 2008/0114339 A1. Hub and blades can consist of the same material which has an elastic configuration so that the blades can be moved between a compressed position placed against the hub and an expanded, radially deployed position. High elasticity of the material is required for this purpose. For example particularly flexible polyurethanes are proposed there as material. Basically, also elastic polymers should be usable.
Basically, the rotor according to the mentioned document should be deformed between the compressed and the expanded form, on the one hand, in a linear range of the stress-strain curve and in addition in a non-linear range of the stress-strain curve in order to be able to perform the necessary large deformation travel.